Reforming system, fuel cell system, and its operation method

Abstract

When terminating power generation by a fuel cell 3 in a fuel cell system 1 , an amount of a raw fuel material introduced to a reforming catalyst 2 a of a reformer 2 is reduced. Here, before the temperature of the reforming catalyst 2 a is lowered to the un-reformed gas generation temperature, an amount of water supplied to the reforming catalyst 2 a is controlled to increase the temperature of the reforming catalyst 2 a . Thus, upon termination of power generation in the fuel cell 3 , no un-reformed gas is generated and the reformed gas is supplied to the fuel cell 3.

The invention claimed is: 
     
       1. An operation method for a fuel cell system comprising
 introducing raw fuel material to a reforming catalyst; 
 introducing water to the reforming catalyst; 
 detecting the temperature of the reforming catalyst, 
 generating a reformed gas by using the reforming catalyst to reform the raw fuel material, 
 using the reformed gas as a fuel in a solid oxide fuel cell; 
 reducing the amount of water introduced to the reforming catalyst to raise the temperature of the reforming catalyst before the detected temperature of the reforming catalyst drops to the temperature at which an un-reformed gas is generated; and 
 reducing the amount of raw fuel material introduced to the reforming catalyst when power generation of the solid oxide fuel cell is terminated. 
 
     
     
       2. The operation method for a fuel cell system of  claim 1 , wherein said reducing the amount of water is conducted by a programmed control unit. 
     
     
       3. The operation method for a fuel cell system of  claim 1 , wherein said reducing the amount of raw fuel material is conducted by a programmed control unit. 
     
     
       4. The operation method for a fuel cell system of  claim 1 , wherein said detecting the temperature of the reforming catalyst is conducted by a plurality of temperature detectors. 
     
     
       5. The operation method for a fuel cell system of  claim 4 , further comprising positioning said temperature detectors on a central axis of a flow path of the raw fuel material. 
     
     
       6. The operation method for a fuel cell system of  claim 1 , wherein said detecting the temperature of the reforming catalyst is conducted by a temperature detector in the flow path of the raw fuel material.